Lamps for underwater use are available for various applications. One such application is for illuminating the water around a landing stage or jetty at night. Use of underwater lamps in this application has a number of uses and advantages. They can be a safety feature, by improving visibility in that area. They can be an aesthetic feature, but importantly they can also be used to attract fish. It will be appreciated that this fish-attracting application can be used not only near to or around a landing stage, but anywhere where there is access to a suitable electricity supply. This can include use from a boat or yacht with an electrical generator. This type of use results in a number of inherent problems. Firstly, the lamp must be secured in some way, either on the sea or river bed near the jetty or near a boat, or to supporting pilework associated with the jetty itself. Seabeds or riverbeds close to the shore are generally very soft due to the deposit of sediment or sand. As a consequence, the stable location of a lamp is problematic. This situation is made worse by motorboat traffic passing over the lights, sometimes at speed, creating a considerable wash or wake which can dislodge a light sitting on the bottom.
An alternative is to affix the lamp to pilework under the jetty, but this may also be problematic since piles can have a number of different profiles.
In addition, it is necessary to be able to change a blown bulb quickly or easily. Some prior art submersible lamps are “sealed for life” units, where a waterproof seal around the bulb is formed by setting the bulb itself in concrete or a resin. Whilst this may be a cost-effective form of construction initially, the unit must be scrapped if the bulb blows.
It is an object of the present invention to overcome or at least mitigate some or all of the problems mentioned above.